Coordination chemistry of a fused triazolopyrazine ligand favoring structural anion···π interactions

King, Andi D.; Woodfine, Sian E.; Hawes, Chris S.

Abstract

The fused heterocyclic ligand 1,2,4-triazolo[4,3-a]pyrazine (L1) is a rigid heterocyclic building block capable of pyrazolate-like coordination modes while retaining neutral electronic character. Here, we examine the coordination chemistry of this species for the first time. While the ligand proved unstable under solvothermal conditions, using mild synthetic conditions we have isolated three new coordination polymers, poly-[Zn(µ2-L1)Cl2] (1), poly-[Ag2(µ3-L1)2(µ2-C3H6O)](BF4)2·C3H6O (2) and poly-[Cu2(µ3-L1)2(µ2-L1)](X-)2 (X- = NO3, 3a; PF6, 3b). Both doubly and triply bridging coordination modes are observed in these species, and close anion···π interactions with the electron deficient ligand backbone are observed in all three complexes as dominant structural features. Although N2 and CO2 adsorption experiments shows the linear solvent channels in complex 3b are not accessible to guests after evacuation, retention of crystallinity on drying and air exposure indicates robust bonding in this species comparable to related fused azolate anions.

Citation

King, A. D., Woodfine, S. E., & Hawes, C. S. (in press). Coordination chemistry of a fused triazolopyrazine ligand favoring structural anion···π interactions. Journal of Coordination Chemistry, 1-12. https://doi.org/10.1080/00958972.2024.2445214

• Journal Article Type: Article
• Acceptance Date: Oct 20, 2024
• Online Publication Date: Jan 24, 2025
• Deposit Date: Feb 10, 2025
• Journal: Journal of Coordination Chemistry
• Print ISSN: 0095-8972
• Publisher: Taylor and Francis
• Peer Reviewed: Peer Reviewed
• Pages: 1-12
• DOI: https://doi.org/10.1080/00958972.2024.2445214
• Keywords: Coordination compounds; coordination polymers; crystal engineering; heterocycles; intermolecular interactions
• Public URL: https://keele-repository.worktribe.com/output/1073149
• Publisher URL: https://www.tandfonline.com/doi/full/10.1080/00958972.2024.2445214